Substituted oxacycloalkanes



Patented Apr. 29, 1952 SUBSTITUTED OXACYGLOALKANES NelsonJ. Leonard,Urbana, 111., assignor to Phillips Petroleum Company,'a corporation ofDela we e NoDrawin'g. Application June 9, 1950, Serial No. 167,255

.18 c im 2 -323) 1 This invention relates ,to substitutedoxacycloalkanes and to their production.

It is an object of this invention to provide substituted oxacycloalkanesas new compositions.

It is another object to provide a process for the production ofsubstituted oxacycloalkanes.

\ It is another object to provide for the interreaction of ahydroperoxycycloalkane with an acid to produce a substitutedoxacycloalkane.

7 Other objects will be apparent to those skilled in the art in thelight of the accompanying discussion anddiselosure.

In accordance with my invention, substituted oxacycloallranes, as newand novel compositions, are produced by the inter-reaction of selectedhydregeroxycycloalkanes with either formic oracetic ac The newcompositions of .my invention are represented by the structural formula:

R e A 0 9,0 H R' where R is an alkylradical containing from 1 to 4carbon atoms, R is of the group consisting of hydrogen and an alkylradical containing from 1- to 3 carbon atoms, the sum of the carbonatoms in R andR'being not greater than 4, A is astable anion of thegroup consisting of acetoxy and formoxy, and-wherein n is an integer ofthe group 3 and 4. These compositions are more specifically referred toas 2-acetoxy-2-alkyloxacycloalkanes, 2 acetoxy2,6-dialkyloxacycloalkanes, 2 acetoxy 2,7 dialkyloxacycloalkanes, 2-formoxy 2 alkyloxacycloalkanes, 2 formoxy- 2,6-dialkylcycloalkanes, and2 form-oxy 2,7-dialkyloxacycloalkanes. R, when an alkyl radical, isselected from the group consisting of methyl, ethyl, n-propyl andisopropyl; R is selected from the group consisting of methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl.

The hydroperoxycycloalkanes reactant materials, sometimes also referredto as naphthene hydroperoxides, are represented by the structuraformula:

wherein R, R, and n are the same as described hereabove with respect tothe new compositions of my invention. Among specific hydroperoxides,

particularly applicable as reactant materials in the process of myinvention, are l-methyl-l-hydroperoxycy clohexane, 1,2 dimethyl 1hydroperoxycyclohexane, 1-ethy1-l-hydroperoxycyclohexane,1,2-diethyl-l-hydroperoxycyclohexane, 1 methyl 2ethyl-1-hydroperoxycyclohexane, 1 propyl 1 hydroperoxycyclohexane, and 1butyl 2 propyl 1 hydroperoxycyclohexane; 1 methyl 1hydroperoxycyclopentane, 1,2 -dimethyl l e hydroperoxycyclopentane, 1ethyl- 1-hydroperoxycyclopentane, 1,2-diethyl-l-hydroperoxycyclopentane,1 methyl 4 2 propyl 1 hydroperoxycyclopentane, 1 propyl J 1 hydrcperoxycyclopentane, and l-butyLZ-propyl-L-hydroperoxycyclopentane, I

l?reparation of the hydroperoxycycloalkane re,- actant materialsdescribedabove can be carried out in any suitable manner. These reactantmaterifilS can be utilized in a pure state or in the rormof aconcentrate containing materials which are inert under the conditions ofthe process r act o v me ho b h h s oper x c c o alkane reactantmaterials can beprepared is disclosed in the copending application ofWilliam M. Hutchinson, Serial No. 69,231, filed January 4, 1949. In thatcopending application is dis- .closed the preparation ofhydroperoxycycloalkanes, by a naphthene hydrocarbon oxidationprocessinvolving the steps: (1) oxidizing a naphse h dmt lrbon withxygen-C ta n n a 2,) r mo l o a 0 a portion o heoxid z a hthen h o rbonrom the resultin oxidation mixture, (3 contacting the resultingresidualperoxide-containing concentrate with a strong non-volatile mineral acid,whereby the contaminants in the' oxidation mixture enter the acid phase,(4) separating a total acid treating mixture into an acid phase and ahydroperoxide phase, and (5) recovering a purified hydroperox ide, or ahydroperoxide solution, as the desired product: I Illustrative of thepreparation of a hydroperoxycycloal ane, as disclosed in thecopendingapplication referred to, is the following, A narrowboilingrange hydrocarbon concentrate comprisingper cent methylcyclohexane ischarged to an oxidation reaction zone to which is alsocharged-compressed oxy en; The teed rate of the m t cy lqhe an c a eisontrol ed to mainain. a i u d l idenq i of 0 min te init reaction zone,which is held at a temperature of C. and at apressure of 500 p. s. i. gThe oxygen feed rate is sufiicient to supply (1.1 mol of oxygen per molof methylcyclohexa'ne; The

oxidation eilluent is discharged to a distillation zone where part orsubstantially all of the unreacted hydrocarbon material is takenoverhead and returned to the oxidation zone. The distillation zone isoperated, preferably under low pressure, so that the kettle temperaturedoes not exceed about 25 C. The residue, or reaction concentrate, ispassed from the distillation zone to a mixing zone where it isintimately mixed by any suitable means, such as by a mechanical stirrer,for about two minutes with a 50 weight per cent aqueous solution ofsulfuric acid. The volume of acid added is controlled so that it isequal to one-tenth that of the reaction product being treated. Theresulting mixture is discharged to a separation zone where it separatesinto an 'acid phase and a hydroperoxide phase. A residence time of eightminutes is sufficient to allow the hydroperoxide phase to separate fromthe acid phase. The temperature in the mixing zone and in the separationzone is held at about -5 C. The hydroperoxide phase is separated fromthe acid phase. The acid treatment may be repeated one or more times ifdesired. Following the acid treatment, the hydroperoxide concentrate istreated with a basic material, such as sodium carbonate, an alkali metalhydroxide, or the like, to remove acidic materials. The hydroperoxidelayer is separated from the aqueous sodium carbonate layer and recoveredas the purified hydroperoxide product.

Hydroperoxide concentrate prepared as above described, containsgenerally from to 90 per cent or more by weight of the hydroperoxide.

Generally, however, when employing a concentrate of this type it ispreferable that it contain at least 30 per cent by weight of thehydroperoxide reactant material. Although a concentrate can be employed,it is preferable that substantially pure reactant materials be utilized.primarily for the reason that smaller volumes of reaction mixtures willbe employed, thus reducing the equipment requirements, and requiredreaction time at any given temperature level.

Although, of course, the. preparative method above discussed for theproduction of hydroperoxycycloalkane reactants utilized in the processof my invention can be used, it is to be understood that my invention isnot limited thereby, and that any known suitable method for thepreparation of these materials can be employed.

Broadly, in the preparation of the substituted 'oxacycloalkanecompositions of my invention, the

v hydroperoxide reactant, and the concentration of the hydroperoxidereactant in the reaction mixture. In general, the'shorter the time ofreaction-the higher the required temperature. At the conclusion of thereaction, the desired product is recovered from the reaction mixture byany desired means, generally by distillation.

I prefer to utilize an excess of acid in the reaction mixture withrespect to'the amount stoichiometrically required for reacting with thehydroperoxide. In general, the weight ratio of acid to thehydroperoxycycloalkane reactant, introduced into the reaction zone, canbe selected from within the limits of 2:1 to 50:1, and from within apreferred range of 5:1 to 20:1., Although acid containing 5 volume percent water can be utilized as a reactant in my process, I prefer thatthe acid reactant be substantially anhydrous for the reason thathydrolysis of the substituted oxacyloalkane product present in thereaction mixture can occur under the process conditions employed, thusreducing the yield of the desired product obtained. However, if desired,an acid reactant containing more than 5 per cent water can be utilized,the consequence being a lower yield of desired oxacycloalkane product.The use of a non-anhydrous acid would, of course, be particularlyadvantageous were it desired that the final reaction product containhydrolysis product of the substituted oxacycloalkane formed.

Reaction temperatures within the limits of 40 to .C'. can be utilized,although more generally within the limits of 60 to 120 C. Preferably, Iutilize a temperature within the limits of from 60 C. to the boilingpoint of the reaction mixture when maintaining the reaction under totalreflux.

Although a pressure far exceeding atmospheric pressure can be utilizedin the practice of my invention, the reaction in most embodiments isefficient at atmospheric pressure, particularly at the boiling point ofthe reaction mixture. However, pressures higher than atmospheric and ashigh as 500 p. s. i. g., or highor can be utilized, if desired.

Contact time is dependent upon the temperature employed, as discussedabove, and can be accordingly varied over a wide range. Generally, areaction time of from 5 minutes to hours can be employed, such aselected time being suitable at a temperature within the broad temperature range already described.- However, when carrying out thereaction employing the preferred temperature range I find that thecontact time can be selected satisfactorily from within the limits of 30minutes to 30 hours.

In a preferred embodiment of the process of my invention I maintain thereactant materials under total reflux at atmospheric pressure andcontinue the refluxing until the hydroperoxide is substantiallycompletely reacted. In this manner the desired product is formed in amaximum yield, and there is no problem of separation of any unreactedhydroperoxycycloalkane reactant material, in the recovery of the desiredproduct from the reaction mixture. I find that when maintaining thereaction mixture under total reflux, the total reaction time required tocompletely react the hydroperoxide reaction with the acid is within thelimits of from 1 to 20 hours. However, some reaction takes placeimmediately, such as for example, after about the first 5 minutes of therefluxing period, but in order to substantially completely react thehydroperoxide, longer times are required.

The substituted oxacycloalkane compositions of my invention are valuablechemical intermediates for the production of hydroxy ketones, anddihydric alcohols or glycols. Production of the hydroxy ketones isreadily accomplished by hydrolysis of the oxacycloalkanes of myinvention. At room temperature these compositions will hydrolyzecompletely, generally in less than one hour. Dihydric alcohols areprepared from the hydroxy reams. thusformed by: hydrogenation.

Advantages of: this invention are illustrated by:' the followingexamples. The. reactants,v and their-proportions, and otherspecific-ingredients are presented asbeing typical and. should not beconstrued to limit the invention unduly.

Example I parts by weight of the hydroperoxidewas, added over-aperiod ofone; minute, with constant stir ring, to 40 parts by weight of glacialacetic acid which had previously been charged to the reactor, Thetemperature of the mixture was maintained at 65 C. for 18 hours at whichtime 80 per cent of the hydroperoxide had reacted.-

The mixture was then refluxed for one hour to complete the reaction.Upon distillation of the material, 3.2 parts of2-acetoxy-2-methyloxepane,

0 El: g: H: C

boiling at 98-104" C./4 mm. Hg, was obtained. Upon analysis of thiscompound, the following results were obtained:

Calcu- Found lateqdr Per cent Carbon 68 62. 76 Per cent Hydrogen 69 9.35 Per cent Oxygen, by difference. .63 27. 87 Molecular Weight 177 172Saponiiication equivalent 185 172 Equivalent weight by saponiflcation.

Ewample II The semicarbazone of 7-hydroxy-2-heptanone, formed byhydrolysis of 2-acetoxy-2-methyloxepane,v was prepared by treatment ofthe 2-acetoxy-2-methyloxepane with an aqueous solution of semicarbazidehydrochloride. The crystalline derivative had a melting point of 129 C.

As will be evident to those skilled in the art, various modificationscan be made or followed, in the light of the foregoing disclosure anddiscussion, without departing from the spirit or scope o f'thedisclosure or from the scope of the claims.

I claim:

1. A process for the production of a substituted oxacycloalkane having acomposition in accordance with the structural formula:

wherein R is an alkyl radical. containing. from,1-

to 4. carbon atoms, R isselected from the group;

R OOH o H (Cans wherein R is an alkyl radical containing from 1 to 4carbon atoms, R isselected from a group consisting of hydrogen and analkyl radical containing from 1 to 3 carbon atoms and n is an integer ofthe group 3 and 4.

2. The process of claim 1 wherein said acid is formic acid and saidhydroperoxycycloalkane is l-methyl-1-hydroperoxycyclopentane.

3. The process of claim 1 wherein said acid is acetic acid and saidhydroperoxycycloalkane is l-methyl-1-hydroperoxycyclohexane.

4. The process of claim 1 wherein said acid is acetic acid and saidhydroperoxycycloalkane is 1,2-dimethyl-1-hydroperoxycyclohexane.

5.' The process of claim 1 wherein said acid is acetic acid and saidhydroperoxycycloalkane is l.-propyl-1-hydroperoxycyclopentane.

6. The process of claim 1 wherein said hydropcroxycycloalkane is1,2-diethyl-1-hydroperoxycyclohexane and said acid is formic acid.

'I. A process for the preparation of 2-acetoxy- Z-methyloxepane,comprising admixing l-methyl l-hydroperoxycyclohexane with acetic acidin a weight ratio of acetic acid to said hydroperoxycyclohexane withinthe limits of 2:1 and 50:1, heating the resultin admixture at atemperature within the limits of 40 and 150 C. under a pressure of from0 to 500 p. s. i. g. and for a period of from 5 minutes to 160 hours,and recovering 2- acetoxy-2-methyloxepane from the resulting reactionmixture as a product of the process.

8. The process of claim 7 wherein said weight ratio is within the limitsof 5:1 to 20:1, said temperature is within the limits of 60 to C., andsaid contact time is within the limits of from 0.5 to 30 hours. a

9. A process for the preparation of 2-formoxy- Z-methyloxacyclohexane,comprising admixing formic acid of at least 95 per cent purity withl-methyl-l-hydroperoxycyc1ohexane, in a weight ratio of said acid tosaidhydroperoxycyclohexane within the limits of 2:1 to 50:1, heating theresulting admixture at a temperature within the limits of 40 and C.under pressure of from 0 to 500 p. s. i. g. and for a period of from 5minutes to hours; andrecovering 2-formoxy-2- methyloxacyclohexane fromthe reaction mixture as a product of the process.

10. A process for the preparation of 2-acetoxy- 2-methyloxepanecomprising admixing l-methyll-hydroperoxycyclohexane with acetic acid ina weight ratio of acetic acid to said hydroperoxycyclohexane within thelimits of 5:1 to 20:1 and heating the resulting admixture at atemperature within the limits of from 40 to 150 C. for a pe-. rind offrom 30 minutes to 30 hours, and recover! ing 2-acetoxy-2-methyloxepanefrom the resulting reaction mixture as a product of the process.

11. The process of claim 10 wherein said 1-methyl-l-hydroperoxycyclohexane is introduced into reaction with saidacid as a concentric containing at least 30 per cent of saidhydroperoxycyclohexane and wherein the resulting admixture is maintainedunder total reflux at atmospheric pressure for a period of from 0.5 to30 hours.

12. The process of claim 10 wherein said hydroperoxide is added to saidacetic acid while the resulting reaction admixture is maintained underreflux, and wherein the total reaction time is within the limits of from1 to 20 hours.

I 13. A substituted oxacycloalkane having a composition in accordancewith the structural formula:

wherein R is an alkyl radical containing from 1 to 4 carbon atoms, R isselected from the group consisting of hydrogen and an alkyl radicalcontaining from 1 to 3 carbon atoms, the sum of the carbon atoms in R.and R is from 1 to 4, n is an integer of the group 3 and 4, andwherein Ais a stable anion of the group consisting of acetoxy and formoxy.

' 14.2 mcetoxy-Z-methyloxepane.

15. A process for the production of a substituted oxacycloalkanecomprising reacting a 1- alkyl 1 hydroperoxycyclohexane, wherein, thealkyl group contains from 1 to 4 carbon atoms, with an acid selectedfrom the group consisting of formic and acetic acid.

16'. A process for the production of a substituted oxacycloalkanecomprising reacting a, 1- alkyl 1 hydroperoxycyclopentane, wherein thealkyl'group contains from 1 to 4 carbon atoms, with an acid selectedfrom the group consisting of formic and acetic acid.

17. A process for the production of a substituted oxacycloalkanecomprising reacting a 1,2- dialkyl-l-hydroperoxycyclohexane wherein eachalkyl group contains from 1 to 4 carbon atoms, with an acid selectedfrom the group consisting of formic and acetic acid.

J 18. A process for the production of a substituted oxacycloalkanecomprising reacting a 1,2- dialkyl-l-hydroperoxycyclopentane' whereineach alkyl group contains from 1 to 4 carbon atoms, with an acidselected from the group consisting of formic and acetic acid.

NELSON J. LEONARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES Linnell, Quart. J. Pharm.Pharmacol. 3, 40-51 (1930) Chem. Abst. 24, 3200 (1930).

13. A SUBSTITUTED OXACYCLOALKANE HAVING A COMPOSITION IN ACCORDANCE WITHTHE STRUCTURAL FORMULA: